“Surface fasteners” are commonly used in many applications, such as disposable incontinence articles (diapers), to join a first surface to a second surface, thereby connecting a first and second portion of an article in face-to-face relationship. Surface fasteners include fastening systems such as “hook & loop” (ie, Velcro™), adhesive or cohesive tapes, magnets, etc. While known to form good connections, surface fasteners can be hard to align, especially when used on diapers & the like in which the product being fastened is applied to a wearer who may move. Also, many types of surface fasteners stick to many things they are not supposed to (ie, tapes to skin, hooks to clothing/carpet. etc.) and can be noisy to unfasten.
Other types of fasteners, generically referred to as “macrofasteners”, which are large, interlocking fasteners, solve many of the problems associated with surface fasteners. Macrofasteners tend to result in good alignment of parts to be connected, typically only interlock with themselves (and do not stick to other objects), & many are very quiet to disengage. Typical macrofasteners include buckles, tabs & slots, hooks and eyes, buttons, and the like.
A drawback of the macrofastener is the rigidity required to make them function correctly. Rigidity is required to prevent the macrofastener from deforming significantly during the engagement process, causing the two components of the fastener to form shapes that do not readily mate together. In addition, the loads that macrofasteners are required to sustain during use may add additional strength requirements requiring even more rigidity of the components to prevent them from deforming or even fracturing during use.
In the field of disposable absorbent articles such as diapers, adult incontinence products, and feminine hygiene products, macrofasteners can be attached to the article and used to join portions of the article to form waist and leg openings. To ensure that the product fits properly and stays in the right location around the torso of the user, a certain tensile force must pass through the waist and the leg openings. The macrofastener must be strong enough to withstand this force sufficiently so it will not be subject to the deformation or fracture as described above
It is common in the field of disposable absorbent articles to use materials such as plastics and polymers to form macrofasteners because of there ability to readily be formed into shapes that are suitable for such applications. The macrofastener may comprise a core component useful in providing strength and a nonwoven cover that provides softness. With polymers, the price of the base material tends to get higher as the materials get stronger and stronger. In addition, it's obvious to those skilled in the art that the more material that is used, the more the components are likely to cost.
There are 2 commonly known ways to make the core fastener elements rigid enough to bear the required loads: 1) use a material that is stronger (ie has a higher modulus of elasticity, or 2) add more of the material to strengthen the components.
Unfortunately, both of these methods of strengthening the core components generally results in a higher cost of manufacture to achieve proper function, and if translated to the consumer, may decrease the economy of the product or result in a poor value to the consumer.
Therefore, to achieve a good value to the consumer, there is a need to have a macrofastener or other force transferring element that has a maximum strength while using 1) a minimum elastic modulus, and 2) a minimum amount of material.